This invention is concerned with novel compounds of structural formula: ##STR1## or a pharmaceutically acceptable salt thereof wherein R is C.sub.1-4 alkyl, C.sub.2-5 alkenyl or phenyl-lower alkyl; and R.sup.1 and R.sup.2 are independently hydrogen, C.sub.1-4 alkoxy or hydroxy.
It is also concerned with processes for the synthesis of the novel compounds, pharmaceutical formulations thereof and with the use of the novel compounds for the treatment of depression and hypertension.
The cis- and trans-isomers of the starting materials, 6-(substituted amino)-6,7,8,9,-tetrahydro-5H-benzocycloheptene-5-ol are described by Yupraphat et al. in Liebigs Ann. Chem., 738, 79-85 (1970) and also Khanna et al., J. Ind. Chem Soc., 51 289 (1974), and are said to have weak sympathomimetic properties.
Surprisingly, it has been found that ring closing through the amino and hydroxyl groups to form a cis- or trans-fused oxazine ring serves to fix the position of the amino group relative to the benzo structure, and the trans- compounds lose their dopaminergic activity and pick up .alpha.-adrenergic agonist (antihypertensive) activity and tetrabenazine antagoinst (antidepressant) activities.